关于本计算器
Plan bedtimes and wake-ups around 90-minute sleep cycles, including time to fall asleep, with optimal 5–6 cycle options highlighted.
睡眠周期计算器
基于90分钟睡眠周期的就寝与起床时间。
就寝时间
21:45
6 个周期 · 9 睡眠
23:15
5 个周期 · 7.5 睡眠
00:45
4 个周期 · 6 睡眠
02:15
3 个周期 · 4.5 睡眠
常见问题
Why 90 minutes?
A full sleep cycle (light, deep, REM) averages about 90 minutes; waking at its end avoids grogginess.
How many cycles?
Most adults need 5–6 cycles (7.5–9 hours); the calculator marks these optimal.
Does fall-asleep time matter?
Yes — add your typical 10–20 minutes so cycles count from real sleep onset.